Investigating the effects of physicochemical properties of vegetable oil on the spore survival duration of fungus Beauveria bassiana Balsamo

The aim of this study was investigating the effect of the vegetable oil and their different physicochemical properties on the spores survival duration of the fungus Beauveria bassiana isolates Iran441C. The experiments were conducted by vegetable oils including rapeseed, soybean, sesame, corn, coconut, grape, olive, almond, sunflower and control. The physicochemical properties of oils including viscosity, soapy index and non soapy index were estimated. The rate of the fungal survival reductions was estimated by calculating the hazard rate, median of spore survival and LT₁₀ and LT₅₀ of spore viability reductions of each vegetable oils and control were estimated by logistic regression. The results showed that the highest median survival and the lowest hazard rate of fungal spore germination were related to rapeseed oil and the lowest median survival and the highest hazard rate of  fungal spore germination were related to almond oil. The lowest and highest gradients of fungal spore viability reductions were related to canola and almond oils. The highest and lowest shelf life limits of fungal spores B. bassiana were equal to 29.84 and 2.42 days for almond oil and rapeseed oil, respectively. The properties of the used oils including viscosity (f=86.5), non soapy index (f=25.12) and soapy index (f=52.87) had significant differences at five percent level. The changes of viscosity and soapy index properties had negative effects and the change of non soapy index had positive effects on reducing the gradient of spore viability. Based on the results, the sesame, rapeseed and sunflower vegetable oils are advisable for the formulation of the fungus B. bassiana isolates IRAN441c.